#custom-button-1,
#wrapper-custom-button-1
  {list-style-image: url("chrome://FromWhereToWhere/content/toolbar-button/button.png");}

/* common style for all custom buttons */
.custombutton                  
  {-moz-image-region: rect( 0px 24px 24px  0px);}

.custombutton:hover     
  {-moz-image-region: rect(24px 24px 48px  0px);}

[iconsize="small"] .custombutton
  {-moz-image-region: rect( 0px 40px 16px 24px);}

[iconsize="small"] .custombutton:hover
  {-moz-image-region: rect(24px 40px 40px 24px);}
